A rights group on Tuesday called for the immediate release of detained Chinese rights lawyer Xie Yang, detailing his lawyers’ reports of his torture in a police-run detention center in the central province of Hunan.

Xie was subjected to confinement in a “hanging chair” made of plastic chairs stacked high above the ground for hours at a time, so that his legs swelled up and he was in excruciating pain, he told his lawyers.

He was also deprived of sleep and repeatedly beaten, humiliated, and taunted with death threats against his family, CHRD cited his lawyers’ notes as saying.

Xie’s lawyer Liu Zhengqing confirmed to RFA that he had filed a formal complaint on his client’s behalf over his treatment in detention, but declined to comment further.

“Right now all I can do is act as his lawyer,” Liu said, adding that no date has yet been set for Xie’s trial on charges of “incitement to disrupt public order and subvert state power.”